Stud driving tool



Jan. 22, 1957 v. R. ER|cKsoN Erm.

STUD DRIVING TOOL Original Filed Dec. 29. 1949 STUD DRIVING TOOLVirginius R. Erickson and Benjamin B. Bullwinkle, Portland, Greg.,assignnrs, by mesne assignments, to Gregori Saw Chain Corp., Portland,Oreg., a corporation of Oregon Original application December 29, 1949,Serial No. 135,744, now Patent No. 2,722,003, dated November 1, 1955.Divided and this application July 18, 1955, Serial No. 522,746

1 Claim. (Cl. 1-44.5)

This application is a division of our co-pending application, Ser. No.135,744, tiled December 29, 1949, and issued as U. S. Letters Patent No.2,722,003, on November 1, 1955.

The present invention relates to stud driving tools of the type employedfor the explosive installation of studs in various types of concrete andsteel structures, and is concerned particularly with methods andapparatus for employing a standard explosive charge by varying theeffestive force of such charge as applied to the stud to obtain adesired selected force for successful installation of a particular studin a particular wall surface.

The present invention provides apparatus for varying of the combustionspace or chamber in which the explosive charge is exploded and for alsovarying the spacing of the stud from the muzzle end of the barrel toinfluence further the energy imparted to the stud by controlling thetime during which the stud is subjected to the driving force beforeemerging from the muzzle end of the barrel.

The above and other objects of the invention are attained in connectionwith certain preferred embodiments of the invention as disclosed anddescribed in connection with the accompanying drawings, in which:

Figure 1 is an elevational View of a stud driving tool with certainparts broken away and shown in section to illustrate the combustionchamber of the tool.

Figure 2 is an enlarged fragmentary view showing the breech plug unitfor obtaining maximum driving force on a stud.

Figures 3 and 4 are views of other sizes of breech plugs for obtainingdifferent eective stud driving forces.

Referring to Figure l, -there is shown a stud driving tool of thecharacter described and claimed in the co-pending applications of Smithand Daugherty, Serial No. 124,078, iled October 28, 1949, for StudDriving Tool, and Erickson and Bullwinkle, Serial No. 130,818, filedDecember 2, 1949, now Patent No. 2,679,645, for Stud Driving Tool. Ingeneral, stud driving tools of this character are adapted to beseparated or broken into two halves including a rear part which containsthe various tiring control parts including, for example, a tiring pincarrier 11, and a front or barrel part 12 of the tool in which thebarrel 13 is included. The barrel 13 is provided with an enlarged rearend 13a which has a threaded connection within the end of the firing pincarrier 11 to connect the two halves of the tool. The barrel 13 is alsoprovided with an enlarged bore in which a combustion chamber or breechplug insert 14 is provided for positioning the stud 16 to be driven andin which the explosive cartridge 13 is mounted for impact by the ringpin of the firing mechanism. rl`he tool is broken in two halves byunthreading 6 the front part 12 at the threaded connection of the barrel2,778,020 Patented Jan. 22, 1957 13 with the firing pin carrier 11 andsliding this part from within the housing of the rear part 10. With theparts disassembled, the breech plug or insert 14 is removed and theselected stud 16 is installed in the barrel, the cartridge 18 is placedin the breech plug 14, and the parts are reassembled as shown in Figurel for a firing operation. Firing is accomplished by placing the end ofthe barrel 13 against the surface into which the stud is to be drivenand pressing or telescoping the barrel assembly 12 and the ring pincarrier 11 back into the other part of the tool until a tiring positionis reached, as disclosed in said applications, and then. aectingrelative turning movement of the central housing and the end grip to rethe tool. At this time the deflector pad structure 19, yieldably mountedabout the barrel 13, is engaged with the surface about the area ofengagement of the end of the barrel so as to provide protection fromflying particles of the Wall surface upon explosive installation of thestud.

As previously stated in accordance with the instant invention, theeective force of the standard explosive charge is varied by positioningthe stud at different predetermined distances along the barrel in spacedrelation with respect to the muzzle end of the barrel and the cartridge.As a result, at the same time tha-t the volume of the combustion chamberis varied, the effective length of the barrel through which the stud isdriven by the explotive charge is also changed, and these two factorsare combined in varying the power control in driving the stud.

As seen in Figure 1 the breech plug 14 is provided with a cylindricalextension 21 which extends within and tits closely within the bore ofthe barrel 13 so that by placing the stud in the barrel and theninserting the breech plug 14, the stud is positioned at a predeterminedspacing both with respect to the cartridge 18 and with respect to themuzzle end of the barrel 13. Preferably the stud 16 is constructed tofrictionally maintain its position Within the barrel, and in the presentinstance, the stud 16 is knurled or dimpled at 16a around its head sothat its position in the barrel will be maintained and yet the stud canbe driven from the barrel by explosive force of the cartridge 18.

Figure 2 shows the highest power or breech plug 1711 which has nocylindrical extension so that the stud is positioned immediatelyadjacent the end of the cartridge 1S. Figures 3 and 4 illustrate otherbreech plugs of the set to select the position of the stud in thebarrel.

While We have shown and described certain preferred methods andapparatus for carrying out the invention it will be understood that theinvention is capable of variation and modification from the form shownso that its scope should be limited only by the scope of the claimappended hereto.

We claim:

In a stud driving tool, a breech plug insert for transitional mountingin the barrel of the tool, said barrel having a bore, said insertincluding a portion of larger References Cited in the tile of thispatent UNITED STATES PATENTS 2,395,354 Temple Feb. 19, 1946 2,533,851Temple Dec. 12, 1950 2,549,993 Temple Apr. 24, 1951

